Question: If $a + b = -5$ and $x + y + z = 10$, what is $-6b - 6a - 2x - 2z - 2y$ ?
Answer: $= -6a - 6b - 2x - 2y - 2z$ $= (-6) \cdot (a + b) + (-2) \cdot (x + y + z)$ $= (-6) \cdot (-5) + (-2) \cdot (10)$ $= 30 - 20$ $= 10$